Slitters are used for cutting rolls of web material such as magnetic tape into thin strands. Gangs of rotary knives are well known for continuously cutting web material into multiple thin ribbons, the width of which may be varied by changing the spacing between adjacent sets of cutting edges.
An example of prior art in the field is U.S. Pat. No. 4,428,265 granted Jan. 31, 1984, owned by Industrial Tools Inc. of Ojai, Calif. This invention is, in some aspects, an improvement over the "Tape Slitter Axial Loading System" disclosed in the patent.
In a typical conventional slitting process, a large roll of tape is advanced through various mechanisms and treatments. To achieve satisfactory results, the tape must be maintained in alignment and held under a predetermined tension depending on the material, cutting pressure applied and other factors. At different sequential phases, the tape is drawn through nip and tension rollers, moved over guide rollers, advanced by drive rollers, slit and passed through cleaning stations--before the resulting multiple strands are rewound on a packing spool.
In some conventional rotary slitters with parallel arbors, it is known to use both cutting edges of the saws. However, there are disadvantages in attempting to switch from engaging one set of cutting edges to the other set of cutting edges during a continuous tape slitting process. For example, the slitting operation must be stopped and the web material is broken which causes slack throughout the drawn section of the roll. At least one of the arbors must be entirely dismantled from the slitting machine or module and prepared for installation. When the removed arbor is finally reassembled, so the opposite cutting edges of the knives are brought into engagement, the web material must be rethreaded manually through the slitter and tension must be restored. This is time consuming, wasteful and inefficient.
The tape slitting adjustment means and process of this invention is an improvement over conventional slitters as well as the one shown in U.S. Pat. No. 4,428,265 and provides unique features for avoiding the operating difficulties and undesired results encountered by conventional systems.